Fine Grade Vermiculite interacts with potassium, calcium, and magnesium in your soil. It also helps to raise the pH slightly of your plants, even though it's a neutral pH of 7.0. Vermiculite is made from compressed dry flakes of a silicate material that is absorptive and spongy. You will receive 1 gallon/26oz 100% course vermiculite, bagged and ready to ship. This vermiculite was tested by Pro-Labs and was certified not to contain any asbestos fibers. ND = None Detected. Buy 2 or more and save. Free Same Day Shipping! Orders are received and processed immediately. Free Same Day Shipping!